K&N 88-88 Isuzu Trooper drop in replacement air filters are awesome. Not only are they easy to install (just pop off the clips on your Trooper stock air box, grab your old filter, and drop your new K&N air filter in), but they are economical AND effective.

Your stock Trooper Isuzu paper air filter is not a good air filter. Not only do paper air filters have to be replaced fairly often, but as dirt and dust accumulates on top of them, they clog and lose their ability to filter air properly. The result is reduced performance and increased strain on your air-hungry Trooper motor. K&N air filters on the other hand, are made from pleated cotton with microfine fibers, and oiled to perfection, resulting in an air filter that actually works better as it gets dirtier (to a point of course). Also, since this Isuzu Trooper air filter is reusable, you only need to clean it with K&N oil every 50,000 miles, instead of replacing it every 1-2 years like you are supposed to with your stock Isuzu Trooper drop-in filter.

Guaranteed for a million miles and 50 state emissions legal.

Unlike most components on cars today, changing your Trooper air filter is easy since, compared to other components in your Trooper, it is easy to get to.

Locate your Trooper's stock airbox.

Undo the metal clips on top to release the cap.

Open the stock air box and remove the old air filter.

If the K&N Replacement drop in filter came with K&N sealing grease (only certain applications will), apply it to the sides of the filter in order to create a better seal in the airbox. If the grease is unusable for any reason, you can use synthetic grease of white lithium. Do not use petroleum-based products instead of grease.

Drop in your K&N Filter into the stock air box

Replace the lid and re-fasten the clips

Enjoy the added power and filter life!

What's the problem with OEM air filters?

Isuzu, in choosing your stock air filter, chose a paper filter design. While paper does an adequate job of filtration, it's rigid solid nature renders it susceptible to clogging relatively quickly. While replacing it with another paper Isuzu air filter may be cheap, paper filters have to be replaced very often. K&N cotton drop in filters on the other hand are washable and reusable. If you were to JUST use OEM paper air filters, then over the life of your Trooper you would actually end up spending more than if you bought just one washable K&N filter and the appropriate amount of K&N cleaning kits.

Why are K&N Replacement Air Filters the best filter for my Isuzu Trooper?

It's all about the design. K&N aftermarket replacement air filters use a cotton filtration medium instead of the stock Trooper paper air filter. Cotton by nature is more fibrous than paper. That means instead of catching particles on the surface of the filter like paper does, it can also catch dust and other debris on the fibers before they even reach the surface of the filter. This process is helped by the fact that K&N uses a specially formulated oil on their cotton to catch and hold debris. As the fibers get dirtier, they actually help filter air even more since their surface area gets bigger, leading to better filtration overall.

Why should I trust K&N to decide what's best for my Trooper?

K&N is the most well known motorsport aftermarket air filter manufacturer in the world. Whether it be stock car racing, go cart racing, or even watercraft racing, every racer knows and respects K&N.
The founders of K&N were motorsport enthusiasts as well. K&N first developed their oiled cotton filters in the harsh and competitive world of desert motocross racing. By experimenting with new media, they were able to come up with their design which helped them to win race after race in the hot and dusty desert environment. If K&N's filter can reign supreme in the unforgiving world of desert dirt bikes, then you can be sure a K&N replacement air filter will work wonders in your Isuzu Trooper as well.

Are K&N Trooper replacement Filters street legal?

Yes! In addition to being a minimally intrusive upgrade (especially when compared to installing more involved products like cold air intakes) K&N specifically designs their Trooper drop in filters to be 50 state emissions compliant, meaning it is completely street legal in the entire United States. You can drive in peace knowing your Isuzu Trooper will not only perform better, but still be legal as well.

How much power can I expect to gain in my Isuzu Trooper with a K&N Drop-In Filter?

It is not guaranteed, since there are a variety of factors that can influence the amount of power you could gain with an air filter, but generally speaking, you can expect a gain of 1-4 horsepower.

Another filter company claims that their filter has filtration levels in the 99th percentile. Does that mean that their filter is better than K&N?

No! Filtration level is not the end-all deciding feature for filters. There are many features that are important in choosing the right filter for your Trooper. Filtration efficiency is just one of them. There is also air flow while getting dirty, the amount of dirt the filter can hold, and the overall effective longevity of the filter.
Basically, what's important is getting the RIGHT amount of clean air into your engine (more air than necessary will not make your car go faster), and how long that filter could do that efficiently. Higher filtration at the expense of air flow is counterproductive, just as higher airflow without filtration is also bad. K&N makes sure to balance all these factors in order to create the best possible filter for your Isuzu Trooper.

Will a K&N replacement air filter damage my Trooper's mass air sensor?

No! There was a company that used to purchase filters from K&N for use with their cold air intakes. Later, they tried to cut out K&N filters and use their own filters instead. It was then that the unfounded rumor began that K&N Air Filters, which are lightly oiled, could lead to a damaged mass air sensor. The fairy tale claims that oil will migrate from the filter over time and get onto the mass air sensor, damaging it.
First off, it has to be remembered that the engine bay of your vehicle is not a pristine surgically clean environment. There is oil, debris, liquids and all kinds of gunk everywhere. You know your engine bay is not an appropriate place to eat your dinner off of. As such, your Trooper's mass air sensor is used to getting small amounts of all this gunk on it all the time. What little oil that might find it's way to your sensor will not be enough to damage it.
To prove this, K&N has created their K&N Customer Protection Pledge. If your dealer ever claims that your Trooper's mass air flow sensor was damaged by a K&N air filter being used properly, they will personally take control of the matter and make sure that your dealer honors their warranty. Rest assured, that to date, there has never been an actual documented case of a K&N Air Filter leading to a damaged mass air sensor.

What comes with a Isuzu Trooper K&N drop-in replacement air filter?

For most applications, K&N replacement filters come with everything you need for installation, which in most cases, is just going to be the pre-oiled filter itself. For most applications, you don't need to do anything else outside of taking the filter out of the packaging in order for it to be ready for use. In some cases, a stock filter box might have been designed with fitment issues, in which case, the K&N filter will come with a little tube of grease to apply to the sides of the filter for a better seal.

How often do you have to clean a K&N Air Filter? Is it possible to clean my Trooper K&N Air Filter too much?

Your stock Trooper filter probably is rated to last 10-15,000 miles before it needs replacement. A K&N Filter though, does not need to be cleaned for 50,0000 miles (though you have to specifically use a K&N Filter Recharger Service Kit).
Also, there is no such thing as cleaning your K&N filter too much. K&N has performed tests where they consecutively cleaned filters over 100 times and they still performed just as well.

How long is the warranty on my Isuzu Trooper K&N drop in air filter?

K&N backs your filter with their industry leading Million Mile Warranty. Basically, if you properly clean your K&N Filter with K&N Recharger Kits every 50,000 miles, K&N guarantees that their filter will last the life of your vehicle. If it does fail with proper use, then K&N will replace the filter free of charge.

Features

Quick and easy drop in install yields 1-4 hp gain

Reusable million mile warranty backed air filter lasts the life of your Trooper

Oiled cotton design works even better as it gets dirtier

Handmade in the USA and UK by K&N, the #1 filter brand in the world

50 state street legal and guaranteed not to void your dealer warranty

Fitment

The Replacement Air Filters offered on this page are designed to specifically fit a Isuzu Trooper produced during the following model years:
1988 or 88. Please also note any specific model notes on the product title at the top of the page.

While it may fit other vehicles, Please try the vehicle search on the center of our main page. or email us if you have any questions.

K&N® Replacement Air Filters
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